Watercraft fin plug assembly

Abstract

The present disclosure describes a fin plug assembly for removably mounting a watercraft fin on a watercraft. In some embodiments the fin plug assembly includes a fin plug, a fin plug finishing insert and in some instances, a shelf-like support that is configured to house the fin plug assembly. Methods of making, methods of installing, and tools for installing the fin plug assembly in a watercraft are also described.

Description

FIELD OF THE INVENTION[0001]This invention relates to watercraft and in particular to assemblies for removably securing fins to the watercraft.BACKGROUND TO THE INVENTION[0002]A number of watercraft make use of fins that project from the water-facing surface of the craft. On planing craft, such as surfboards, the fins are typically foil-shaped to enhance the directional stability of the craft during high speed planing motion and to facilitate turning.[0003]On watercraft such as surfboards the use of removable fins has become quite commonplace. These fins are removably and interchangeably fitted to the watercraft by means of fin mounting systems embedded in the water-facing surface of the craft, the fin mountings typically having a cavity that is configured to receive the base of the fin. Various securement mechanisms are used to secure the fin base in the mounting system cavity.[0004]In conventional surfboard manufacturing terminology, the fin mounting systems are referred to as fin...

AI Technical Summary

Benefits of technology

[0023]Besides the inherent strength of a concave collar shape, the raised perimetral rim constitutes a torsion band that extends about the perimeter of the fin plug. The torsion band serves to resist torsional deformation of the fin plug in use. The resistance to torsional stress and the general rigidity of the fin plug assembly is further enhanced by the fin plug finishing insert which, when bonded to the fin plug, provides further torsional resistance.

[0025]Besides reducing the mass of the fin plug, which is in itself desirable, the interstitial webs and the apertures in the collar provide additional relief formations and mechanical key for subsequent bonding of the fin plug to the watercraft.

[0026]To provide even further surface relief, the surfaces of the interstitial webs may be grooved and in a preferred embodiment of this form of the invention, the web edges are rebated.

[0036]To accommodate and retain the fin plug securely, the shelf-like support might, depending on the complexity of the fin plug shape, require a central aperture with a relatively complex shape in order to complement the shape of the fin plug. In contrast, the external shape of the shelf-like support can be relatively simple to facilitate installation in the core of the watercraft, where a receiving cavity of relatively simple shape can be formed to accommodate the relatively simple external shape of the shelf-like support.

Problems solved by technology

One of the problems encountered with known fin plugs arises from the characteristics of surfboard construction.

In typical installations, the outer laminate of the surfboard is extended partially over the fin plug, but given the size limitations imposed by the locations where the fin plugs are installed on the surfboard, the laminate contact surface offered by the fin plug is generally insufficient to provide any real support to the fin plug in resisting the torsional loads imposed on the fin plug.

However, the low-density foam of the core generally does not have sufficient strength to resist the torsional fin plug loads without deformation or weakening of the surrounding foam over time, with consequential reduction in performance of the fin, cracking and shattering of the laminate in the vicinity of the fin plug and eventually delamination of the laminate from the core.

These fin plugs are typically of injection mouldable plastics, which generally does not bond well to the polyester resin most commonly used to laminate modern watercraft, unless the fin plug is treated, for instance by sanding, to provide some form of mechanical key and even this does little to improve bonding of the plastic to the resin.

In addition, it will be appreciated that this introduces a secondary process that increases the cost and complexity of fin system installation.

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